1. Field of the Invention
The present invention relates to a process for producing deformable acrylic panels with increased resistance to abrasion and scratching preferably for use with sanitary articles manufactured by the deep-drawing process. An example of sanitary articles would include bathtubs, shower tubs or the like.
2. The Prior Art
The prior art describes processes for manufacturing plastic sanitary articles based on polymethylmethacrylate. Plastic sanitary articles, like bathtubs or shower tubs, are mostly referred to as acrylic tubs and have properties which differ from steel-enamel tubs. German Patent DE 43 44 577 (A1), describes a process for the manufacture of acrylic tubs based on polymethylmethacrylate. It is known from the '577 patent to add particular inorganic fillers to the polymethylmethacrylate (PMMA). These inorganic fillers contain relatively fine particles; however, their particle size is still in the range of 20 to 60 .mu.m. In the process disclosed in the '577 patent, the sanitary articles are not deep-drawn but rather produced by the casting resin process. The total casting resin suspension contains the so-called fillers, so that the latter are distributed over the entire volume of the finished PMMA-panel. In the above process, fillers are also used for the purpose of enhancing the thermal stability of the plastic sanitary articles.
Similarly, German patent DE 43 13 715 (A1), specifies the manufacture of polymer materials based on PMMA using particulate inorganic fillers whose size is greater than 10 .mu.m. Foamed PMMA-materials, manufactured with this process, are less suitable for producing sanitary articles with surfaces exhibiting special resistance to abrasion and scratching. In addition, no provision is made for deforming the polymer materials by the deep-drawing process.
An expert in the field of sanitary article manufacture knows that the resistance of the surface of conventional acrylic tubs to abrasion and scratching is inadequate in most cases. After prolonged use, these acrylic tubs show traces of surface scratching and eventually become dull.